1. Field of the Invention
The present invention relates generally to a computer performance modeling system. More particularly, the present invention relates to such modeling systems which use aggregation techniques in a layered system model.
2. Description of Related Art
Massively parallel processors (MPPs) are currently being used in commercial decision-support applications that require large databases. For example, the Teradata DBC/1012 MPP from AT&T Global Information Solutions shown in FIG. 1 has a system architecture which allows up to 1,024 processors, communicating through a proprietary interconnection system (i.e., Ynet). This MPP has two types of processing nodes, including: Interface Processors (IFPs), and Access Module Processors (AMPs). The IFPs use Intel 80386 processors and the AMPs use Intel 80486 processors. Each processor can have up to 8 Megabytes of random access memory (RAM). In addition, each AMP may be equipped with up to four disks. In this MPP, an IFP receives database requests from a host computer system (e.g., an IBM mainframe computer). The IFP parses a request into one or more serial or parallel processing "Steps.@ These Steps are dispatched to one or more AMPs. The AMPs execute the Steps by accessing and/or modifying the databases based upon the particular request Steps received. Upon completion of these Steps, each AMP sends the response to the originating IFP so that the response can be forwarded to the host computer system.
Such MPPs are extremely complex to design, debug, and analyze. Due to the prohibitive cost of maintaining very large systems for the sole purpose of performance measurement, the ability to model such large system performance in a low cost, simple form is of particular interest. Also, a way to gain an in-depth understanding of subsystems interaction and performance sensitivity to various system parameters is needed. Such a MPP performance model also can be used with appropriate modifications to support the performance analysis of future MPPs.
Therefore, a need exists for an MPP system model which can be used to support the performance analysis of both the current system design and suggested upgrades before their installation at customer sites. The MPP system model ideally will fulfill many requirements covering the usual performance analysis tasks: identification of bottlenecks, comparing alternative upgrades suggested by system developers, understanding subsystems interaction, estimation of performance sensitivity to system parameters, etc. In addition, for greater cost savings, the MPP system model should be capable of modeling a 512-processor configuration in a Model Execution Time (MET) to Simulated Database Computer (DBC) Time (SDT) ratio of less than 100:1. Accuracy requirements stipulate that the system model's throughput estimates preferably be within 20% of an actual system throughput and that the system model's response time estimates preferably be within 30% of actual system response time. For greater flexibility and ease of use, at least two levels of users should be supported. In particular, users should have differing user interfaces to support those that will run the model while varying only system parameter values and those that will modify algorithms and system features, in addition to system parameter values.
The present invention provides a solution to this and other problems, and offers other advantages over the prior art.